Low-voltage connection with safety circuit and method for determining proper connection polarity
First Claim
1. A safety circuit for use in establishing connections between low-voltage systems to transfer energy from a first low-voltage system to a second low-voltage system, comprising:
- a pair of input terminals;
a pair of output terminals;
a detection circuit operatively connected to the input terminals and the output terminals for detecting whether the input terminals and the output terminals are properly connected to first and second low-voltage systems, respectively;
a connection-controlling circuit configured to electrically connect the input terminals to the output terminals only when a proper connection has been detected and using a soft start procedure that reduces inductive voltage spikes; and
a transistor protection s stem for protecting transistors used to electrical connect the input terminals to the output terminals, the transistor protection system comprising a microcontroller that maintains a thermal model of heating of the transistors when power is flowing and a thermal model of cooling of the transistors when power is not flowing, that monitors for over-current conditions that could destroy the transistors, and that monitors for under-voltage conditions on the supply side.
1 Assignment
0 Petitions
Accused Products
Abstract
A safety circuit used in low-voltage connecting systems leaves the two low-voltage systems disconnected until it determines that it is safe to make a connection. When the safety circuit determines that no unsafe conditions exist and that it is safe to connect the two low-voltage systems, the safety circuit may connect the two systems by way of a “soft start” that provides a connection between the two systems over a period of time that reduces or prevents inductive voltage spikes on one or more of the low-voltage systems. When one of the low-voltage systems has a completely-discharged battery incorporated into it, a method is used for detection of proper polarity of the connections between the low-voltage systems. The polarity of the discharged battery is determined by passing one or more test currents through it and determining whether a corresponding voltage rise is observed.
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Citations
20 Claims
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1. A safety circuit for use in establishing connections between low-voltage systems to transfer energy from a first low-voltage system to a second low-voltage system, comprising:
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a pair of input terminals; a pair of output terminals; a detection circuit operatively connected to the input terminals and the output terminals for detecting whether the input terminals and the output terminals are properly connected to first and second low-voltage systems, respectively; a connection-controlling circuit configured to electrically connect the input terminals to the output terminals only when a proper connection has been detected and using a soft start procedure that reduces inductive voltage spikes; and a transistor protection s stem for protecting transistors used to electrical connect the input terminals to the output terminals, the transistor protection system comprising a microcontroller that maintains a thermal model of heating of the transistors when power is flowing and a thermal model of cooling of the transistors when power is not flowing, that monitors for over-current conditions that could destroy the transistors, and that monitors for under-voltage conditions on the supply side. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of testing a polarity of a discharged battery connected to a first low-voltage system comprising:
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connecting a test current source to a first low-voltage system containing a discharged battery; supplying a first test current to the first low-voltage system; measuring a first resulting voltage of the first low-voltage system; supplying a second test current to the first low-voltage system, wherein the second test current is in an opposite direction to the first low-voltage system; and measuring a second resulting voltage of the first low-voltage system. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A jumper cable for use in establishing connections between low-voltage systems to transfer energy from a first low-voltage system to a second low-voltage system, comprising:
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a safety circuit comprising; a pair of input terminals; a pair of output terminals; a detection circuit operatively connected to the input terminals and the output terminals for detecting whether the input terminals and the output terminals are properly connected to first and second low-voltage systems, respectively; a connection-controlling circuit configured to electrically connect the input terminals to the output terminals only when a proper connection has been detected and using a soft start procedure that reduces inductive voltage spikes; and a transistor protection system for protecting transistors used to electrically connect the input terminals to the output terminals, the transistor protection system comprising a microcontroller that maintains a thermal model of heating of the transistors when power is flowing and a thermal model of cooling of the transistors when power is not flowing, that monitors for over-current conditions that could destroy the transistors, and that monitors for under-voltage conditions on the supply side; a first cable connected to the input terminals and comprising first contact clamps for connecting to the first low-voltage system; and a second cable connected to the output terminals and comprising second contact clamps for connecting to the second low-voltage system. - View Dependent Claims (19, 20)
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Specification